Preform and method for manufacturing a multi-layer blown finish container

ABSTRACT

A preform and method used to make a container which has a blown wide-mouth finish and a multilayer wall structure. The injection molded preform has a multi-layer container body forming portion, a mono-layer moil forming portion and a blown finish forming portion located between the container body forming portion and the moil forming portion. The preform is blown into an intermediate article consisting of a blown finish wide-mouth multi-layer container and a mono-layer moil portion which is severed from the intermediate article and recycled. The multilayer wall structure can include at least one layer of a gas barrier material, a cost-effective recycled material, or a material which strengthens and/or lightweights the container.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a 371 of PCT/US01/19533 which was filed on Jun. 19,2001 and which claims the benefit of priority of U.S. Provisional PatentApplication No. 60/214,582 filed on Jun. 27, 2000.

FIELD OF THE INVENTION

The present invention relates to wide mouth blow-molded plasticcontainers, and more particularly, the present invention relates to apreform and method for use in efficiently manufacturing multi-layer widemouth blow-molded plastic jars suitable for hot-fill applications.

BACKGROUND OF THE INVENTION

In the manufacture of blow-molded plastic bottles for containingliquids, such as beverages, it is customary to utilize aninjection-molded preform having an injection molded threaded finishwhich ultimately forms the threaded finish of the container blown fromthe preform. The preform may be injection molded from a variety ofdesirable plastic materials, such as polyethylene terephythalate (PET),and may include an encapsulated gas barrier layer, such as an ethylenevinyl alcohol copolymer (EVOH) which is highly impermeable to oxygenwhen dry. Examples of multi-layer containers and preforms are disclosedin U.S. Pat. No. 4,526,821 issued to McHenry et al.; U.S. Pat. No.4,535,901 issued to Okudaira et al.; U.S. Pat. No. 4,728,549 issued toShimizu et al.; and U.S. Pat. No. 4,550,043 issued to Beck.

Some containers, particularly those molded of PET, have been utilized inhot fill applications where the blown container is filled with abeverage heated to a temperature in excess of 180° F. (82° C.), cappedimmediately after filling, and allowed to cool to ambient temperatures.In such containers, vacuum absorption panels are typically provided inthe body of the container to accommodate vacuum induced shrinkageresulting from cooling of the container contents. In such containers,the injection molded threaded finish undergoes a minimal amount ofdistortion during the hot fill process. An example of a hot-fillable,multi-layer container having an injection molded finish is provided byU.S. Pat. No. 4,818,575 issued to Hirata et al.

For quite some time, there has been a need in the marketplace for aso-called wide-mouth container for hot-fill applications. A wide mouthcontainer enables the consumer to scoop-out viscous contents which arenot readily flowable. Such examples of viscous products includeapplesauce, spaghetti sauce, relish, pickles, beets, baby foods,sauerkraut, jelly, mayonnaise, and salad dressings to name a few.Examples of wide-mouth plastic containers are disclosed in U.S. Pat.No.: 5,092,474 issued to Leigner; U.S. Pat. No. 5,261,544 issued toWeaver, Jr.; Pat. No. D.423,936 issued to Smith et al.; Pat. No.D.420,593 issued to Denner et al.; and Pat. No. D.402,563 issued toPrevot et al.

In the early 1980's, attempts were made to produce hot-fillable PETcontainers having blown wide mouth finishes. To this end, a preform withan injection molded finish was blow-molded to form anintermediate-article which included a blown container and a moil portionintegrally extending from the blown threaded finish portion of the blowncontainer. The injection molded finish is part of the moil portion whichis severed from the intermediate article thereby leaving a finishedwide-mouth container having a blown finish with external threads. Thismanufacturing technique and the resulting containers are disclosed inU.S. Pat. No.: 4,665,682 issued to Kerins et al.; U.S. Pat. No.4,618,515 issued to Collette et al.; and U.S. Pat. Nos. 4,576,843 and4,496,064 issued to Beck et al. The above referenced Kerins patent alsodiscloses the use of a five layer wall structure consisting of threelayers of PET and two encapsulated layers of a barrier material, SARAN.

There is a current need for a novel and improved hot-fillable wide mouthcontainer which includes an embedded gas barrier layer and which isparticularly suited for packaging viscous food products.

OBJECTS OF THE INVENTION

With the foregoing in mind, a primary object of the present invention isto provide a commercially satisfactory wide-mouth blow-molded containerthat has a multi-layer construction.

Another object of the present invention is to provide a preform andmethod which can be used to manufacture a multi-layer wide-mouthblow-molded plastic container and which form an intermediate articlehaving a moil portion consisting essentially of a primary containermaterial so that, after the moil portion is severed from the container,the moil portion can be readily and efficiently recycled.

Still another object of the present invention is to provide amulti-layer wide mouth blow-molded plastic container which has a blownfinish that at least partially includes an encapsulated layer of asecondary material and that resists distortion resulting fromhot-filling.

A further object of the present invention is to provide a method ofmanufacturing a multi-layer wide-mouth container which enablescommercially acceptable hot fillable wide-mouth plastic containers to beproduced by means of high speed manufacturing equipment in an economicalmanner that ensures consistent quality and performance.

SUMMARY OF THE INVENTION

More specifically, according to one aspect of the present invention, amethod of making a multi-layer blow-molded plastic container having anexternally-threaded wide-mouth finish for receiving a removable closureis provided. To this end, a tubular preform is provided having acontainer body forming portion, a moil forming portion and a blownfinish forming portion. The container body forming portion includes aclosed bottom end of the preform and has a multi-layer structureincluding at least one layer of a secondary material located betweeninner and outer layers of a primary container material. The moil formingportion includes an open top end of the preform and has a mono-layerstructure consisting essentially of the primary container material sothat it can be readily recycled. The blown finish forming portion islocated between the container body forming portion and the moil formingportion. Preferably, the secondary material extends into the blownfinish forming portion of the preform and terminates therein withoutextending into the moil forming portion of the preform.

The above referenced preform is preheated and then disposed into a moldcavity having a surface with a container body forming region, a blownfinish forming region superadjacent the body forming region, and a moilforming region superadjacent the blown finish forming region. Thepreform is then distended against the surface of the mold cavity to forman intermediate container article including a multi-layer blow-moldedplastic container having a blown externally-threaded wide-mouth finishand a moil extending upwardly from the blown finish. The moil is severedfrom the intermediate container article and is recycled post-manufacturebut pre-consumer.

According to other aspects of the invention, a preform is providedhaving the above described structure and a multi-layer wide-mouthcontainer is produced according to the above referenced process.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the presentinvention should become apparent from the following description whentaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic longitudinal view of a portion of a blow moldcavity illustrating a preform mounted in the cavity prior to blowing;

FIG. 2 is a side elevational view of an intermediate article having amoil formed when the preform shown in FIG. 1 is blown within the moldcavity;

FIG. 3 is an enlarged longitudinal view of the preform illustrated inFIG. 1 showing the multi-layer structure of the preform;

FIG. 4 is a side elevational view of the wide mouth container formedafter the moil portion illustrated in FIG. 2 has been severed;

FIG. 5 is a greatly enlarged cross sectional view of the portion of FIG.4 delineated as FIG. 5; and

FIG. 6 is a side elevational view of an alternate wide-mouth container.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT AND METHOD

The purpose of the present invention is to provide a multi-layer,wide-mouth, blow-molded plastic container, or jar, such as illustratedin FIGS. 4 and 6. However, the present invention is not limited to anyspecific multi-layer, wide-mouth, plastic container structure. Forinstance, FIG. 4 illustrates a wide-mouth container 10 having aplurality of peripherally spaced flex panels 12 which enable thecontainer 10 to be used in hot-fill applications, and FIG. 6 illustratesa wide-mouth container 110 having a pair of offset flex panels 112 whichenable the container 110 to be used in hot-fill applications. Of course,the present invention is equally applicable to multi-layer wide-mouthcontainer structures which do not include flex panels and which can beused in vacuum fill, cold fill, or any other type of processing method.

For purposes of the present invention, and as will be discussed indetail, important aspects of the subject containers are that they have ablown wide-mouth finish and a multilayer structure which includes one ormore layers of a secondary container material substantially encapsulatedwithin a primary container material. Thus, such a structure may includethree, five or more alternating layers of primary and secondarycontainer materials. Examples of secondary materials include re-cycledPET (PCR), PEN, EVOH, nylon and other gas barrier or recycled materials.An example of a primary material is PET.

The illustrated containers, 10 and 110, each have a wide mouth threadedfinish, 20 and 120. For present purposes, a wide-mouth finish is definedas a finish having an outside diameter greater than about 2.0 inches, or50 mm. Wide mouth finishes are preferred when the product contained is aviscous food product, such as applesauce or the like. In addition, thecontainers 10 and 110 each have a generally cylindrical container body,14 and 114, including a base, 16 and 116, and a dome, 18 and 118. Asstated, the container 10 has a plurality of peripherally spaced vacuumpanels 12 provided in the body 14 for accommodating vacuum inducedvolumetric shrinkage and supporting a label, as well known in the art.The container 110 has a pair of flex panels 112 provided in the body 114enabling the container 110 to be utilized in hot-fill processing.

The containers 10 and 110 include an embedded layer of a secondarymaterial. For instance, as illustrated in FIG. 5, a secondary materiallayer 22 is embedded within the walls of the container 10. The secondarymaterial layer 22 is substantially encapsulated within the walls of thecontainer by inner and outer layers, 24 and 26, of a primary containermaterial. The primary container material may be, for instance, PET, andthe secondary material may be, for instance, a gas barrier material (ie.EVOH or nylon), a recycled material (ie. PCR), or other materials (ie.PEN).

As best illustrated in FIG. 5, the secondary material layer 22 extendswithin the blown finish 20 but has a terminal end 22 a which terminatesbelow a top sealing surface 28 of the container 10. Thus, the secondarymaterial layer 22 extends continuously through the container body 14,base 16, and at least partially through the blown finish 20. The onlyexception may be at the sprue 30 of the base 16 where the secondarymaterial layer 22 may, or may not, be permitted to bleed through theouter layer 26 of the primary container material. In one contemplatedembodiment, the secondary material layer 22 is provided as a single thinlayer which forms no greater than about 20% of the thickness of the wallof the container.

As stated above, an important aspect of the container according to thepresent invention is that it is formed with a blown finish. Thisprovides a significant cost savings relative to identically structuredcontainers having injection molded wide-mouth finishes. However, aproblem with wide-mouth plastic containers, particularly those that areformed by blow molding techniques, is the potential for undesirabledistortion of the finish due to hot filling or other processing and dueto subsequent storage and handling. Distortion is undesirable because adistorted threaded finish cannot function well in automatic cap applyingequipment. Moreover, an undistorted finish is desirable to ensure sealintegrity after the cap has been applied and tightened.

A preform and a method for providing a distortion-resistant threadedfinish on a multi-layer wide-mouth container is provided by the presentinvention. To this end, as illustrated in FIG. 1, a specially designedpre-heated preform 32 is provided in a mold cavity 34. The preform 32blown in the mold cavity 34 forms an intermediate container article 36,such as illustrated in FIG. 2. The intermediate container article 36 hasa moil portion 38 which is subsequently severed to ultimately providethe container 10 as illustrated in FIG. 4.

As best illustrated in FIG. 3, the preform 32 has a tubular elongatebody with a closed end 46 and an open end 48 surrounded by a peripheralflange 50 which supports the preform 32 in the mold cavity 34. Thepreform is injection molded and can be divided longitudinally intovarious regions corresponding to various regions of the intermediatecontainer article 36 and ultimately, the container 10 itself.

A moil forming portion 52 is located adjacent the open end 48 of thepreform 32. This portion of the preform 32, when blown, forms the moil38 of the intermediate article 36. After being severed, the primarycontainer material in the moil 38 can be recovered and recycled for usein making additional preforms. However, if the moil 38 containssecondary material, significant costs are associated with the separationof the secondary material from the primary container material duringrecycling. According to the present invention, the secondary materiallayer 22 in the preform 32 is intentionally formed such that itterminates below the moil forming portion 52 so that the moil 38consists essentially of the primary container material and can bereadily recycled.

A container body forming portion 54, which includes a base formingportion, is located adjacent the closed end 46 of the preform 32. Asillustrated in FIG. 3, the secondary material layer 22 extendscontinuously throughout the container body forming portion 54 of thepreform 32 except for where it bleeds through at the sprue 30. Thus, thepreform 32, when blown, forms a multi-layer container body 14. Forexample, the multi-layer construction can be a three layer constructionof PET/EVOH/PET; however, five or more layers can also be utilized anddifferent primary and secondary materials can be utilized. By way ofexample, and not by way of limitation, the total thickness of the wallof the preform can be about 5 mm or 0.200 inches, and the secondarymaterial layer can be centered in the wall and have a thickness of about0.005 inches.

A blown finish forming portion 56 of the preform 32 extends between themoil forming portion 52 and the container body forming portion 54. Theblown finish forming portion 56, when blown, forms the blown finish 20of the container 10. The blown finish 20 includes a top sealing surface28 and external threads 58. The top sealing surface 28 defines a planein which the moil portion 38 interconnects with the blown finish 20 andwhere the moil portion 38 is severed from the container 10. Asillustrated, the secondary material layer 22 extends into the blownfinish forming portion 56 of the preform 32 but does not extendcompletely through the blown finish forming portion 56. Thus, asillustrated in FIG. 5, the secondary material layer 22 terminates aspaced distance below the top sealing surface 28 and is encapsulatedwithin the primary container material adjacent the top sealing surface28 of the container 10. Alternatively, the secondary material layer 22can terminate below the blown finish portion 56 of the preform 32 sothat the blown finish portion 56 is mono-layer and consists essentiallyof the primary container material. If additional gas barrier protectionis desired in a mono-layer blown finish portion, the finish can beintentionally blown with a sufficient thickness to offset the lack ofsecondary material.

The mold cavity 34 has an interior mold surface 60 which corresponds tothe overall outer configuration of the intermediate container article 36below the preform flange 50. To this end, the mold cavity 34 has asurface 60 with a container body forming region 62, a blown finishforming region 64 superadjacent the body forming region 62, and a moilforming region 66 superadjacent the blown finish forming region 64. SeeFIG. 1.

When the preform 32 is blown in the mold cavity 34, it forms a threadedfinish 20 having a wall of substantially uniform thickness. After themoil 38 is cut from the container 10, the upper end of the finish 20 hasan inturned flange 68 as illustrated in FIG. 5. The inturned flange 68reinforces the threaded finish 20 against ovalization and therebyenables it to resist distortion after hot-filling, both before and aftercapping. Moreover, the top sealing surface 28 of the inturned flange 68is inclined at about a 5° angle to provide a smoothaccurately-controlled, axially resiliently deformable surface forsealing against the inner surface of a closure (not shown).

In the method of the present invention, the above described preform 32is pre-heated to a temperature, for instance, of about 120° C. andplaced in the above described mold cavity 34. The preform 32 isdistended, or blown, against the surface 60 of the mold cavity 34 toform the above described intermediate article 36. The moil portion 38 ofthe article 36 is severed from the container 10 and is recycled. Thecontainer 10 can be utilized in hot-fill or other applications withoutthe occurrence of distortion. The secondary material layer 22 of thecontainer 10 can function, for instance, to reduce the amount of gaswhich can pass through the wall in a given period so that an acceptablepackage shelf life can be provided for a wide variety of viscous foodproducts. Alternatively, the secondary material layer 22 can be utilizedas a cost-effective filler material to reduce material costs, or it canbe utilized to increase the strength of the container, to lightweightthe container, or to provide a container capable of being filled athigher hot-fill temperatures.

While a preferred method, preform and container has been described indetail, various modifications, alterations and changes may be madewithout departing from the spirit and scope of the present invention asdefined in the appended claims.

I claim:
 1. A method of making a multi-layer blow-molded plasticcontainer (10, 110) having an externally-threaded wide-mouth finish (20,120) for receiving a removable closure, comprising the steps of:obtaining a tubular preform (32) having a container body forming portion(54) which includes a closed bottom end (46) of said preform (32), amoil forming portion (52) which includes an open top end (48) of saidpreform (32), and a blown finish forming portion (56) located betweensaid container body forming portion (54) and said moil forming portion(52), said body forming portion (54) of said preform (32) having amulti-layer structure including at least one layer (22) of a secondarymaterial located between inner and outer layers (24, 26) of a primarycontainer material, and said moil forming portion (52) of said preform(32) having a mono-layer structure consisting essentially of saidprimary container material; preheating said preform (32); disposing saidpreheated preform (32) into a mold cavity (34) having a surface (60)with a container body forming region (62), a blown finish forming region(64) superadjacent said body forming region (62), and a moil formingregion (66) superadjacent said blown finish forming region (64);distending said preheated preform (32) against said surface (60) of saidmold cavity (34) to form an intermediate container article (36)including a multi-layer blow-molded plastic container (10) having ablown externally-threaded wide-mouth finish (20) and a moil (38)extending upwardly from said blown finish (20); and severing said moil(38) from said intermediate container article (36) at a location thatprovides a severed moil (38) consisting essentially of said primarycontainer material.
 2. A method according to claim 1, wherein saidsecondary material extends substantially entirely through said bodyforming portion (54) and at least partially into said blown finishforming portion (56) of said preform (32), and wherein said secondarymaterial terminates within said blown finish forming portion (56) belowsaid moil forming portion (52).
 3. A method according to claim 2,wherein said secondary material is a gas barrier material.
 4. A methodaccording to claim 2, wherein said secondary material is recycledmaterial.
 5. A method according to claim 2, wherein said secondarymaterial is PEN.
 6. A method according to claim 2, wherein saidmulti-layer structure consists of a three layer construction, andwherein said primary container material is PET.
 7. A method according toclaim 2, wherein said obtaining step includes injection molding of saidpreform (32).
 8. A method according to claim 7, further comprising thestep of recycling said moil (38) after said moil (38) has been severedfrom said intermediate container article (36), and utilizing saidrecycled moil (38) in the manufacture of more of said preforms (32). 9.A method according to claim 8, further comprising filling said container(10, 110) with a viscous food product and sealing said container (10,110) with a closure.
 10. A method according to claim 8, wherein saidviscous food product is hot-filled into said container (10, 110) andwherein said container (10, 100) has a wide-mouth jar-like shape.
 11. Amulti-layer blow-molded plastic container (10, 110) having anexternally-threaded wide-mouth finish (20, 120) for receiving aremovable closure prepared by a process comprising the steps of:obtaining a tubular preform (32) having a container body forming portion(54) which includes a closed bottom end (46) of said preform (32), amoil forming portion (52) which includes an open top end (48) of saidpreform (32), and a blown finish forming portion (56) located betweensaid container body forming portion (54) and said moil forming portion(52), said body forming portion (54) of said preform (32) having amulti-layer structure including at least one layer (22) of a secondarymaterial located between inner and outer layers (24, 26) of a primarycontainer material, and said moil forming portion (52) of said preform(32) having a mono-layer structure consisting essentially of saidprimary container material; preheating said preform (32); disposing saidpreheated preform (32) into a mold cavity (34) having a surface (60)with a container body forming region (62), a blown finish forming region(64) superadjacent said body forming region (62), and a moil formingregion (66) superadjacent said blown finish forming region (64);distending said preheated preform (32) against said surface (60) of saidmold cavity (34) to form an intermediate container article (36)including a multi-layer blow-molded plastic container (10) having ablown externally-threaded wide-mouth finish (20) and a moil (38)extending upwardly from said blown finish (20); and severing said moil(38) from said intermediate container article (36) at a location thatprovides a severed moil (38) consisting essentially of said primarycontainer material; said secondary material extending substantiallyentirely through said body forming portion (54) and at least partiallyinto said blown finish forming portion (56) of said preform (32), andsaid secondary material terminating within said blown finish formingportion (56) below said moil forming portion (52); said multi-layerstructure consisting essentially of a three layer construction of anoutermost layer (26) of PET, a core layer (22) of secondary material,and an innermost layer (24) of PET, said core layer (22) being selectedfrom the group consisting of EVOH, nylon, PCR and PEN; and saidcontainer (10, 110) having at least one vacuum flex panel (12, 112). 12.An injection molded preform (32) for forming an intermediate article(36) which is used to form a blow-molded container (10, 110) having awide-mouth blown finish (20, 120) with external threads and whichincludes a moil portion (38) extending integrally from said blownfinish, said preform (32) comprising: an injection-molded elongatetubular body having a closed bottom end (46), an open top end (48) witha peripheral flange (50), a container body forming portion (54) whichincludes said closed bottom end (46), a moil forming portion (52) whichincludes said open top end (48), and a wide-mouth blown finish formingportion (56) located between said container body forming portion (54)and said moil forming portion (52); at least a portion of said bodyforming portion (54) having a multi-layer construction including atleast one layer (22) of a secondary material located between inner andouter layers (24, 26) of a primary container material; and said moilforming portion (52) having a mono-layer construction consistingessentially of said primary container material.
 13. An injection moldedpreform (32) according to claim 12, wherein said secondary materialextends substantially entirely through said body forming portion (54)and into said blown finish forming portion (56) of said tubular body,and wherein said secondary material terminates within said blown finishforming portion (56) below said moil forming portion (52).
 14. Aninjection molded preform (32) according to claim 13, wherein saidsecondary material is selected from the group consisting of a gasbarrier material and a recycled material.
 15. An injection moldedpreform (32) according to claim 13, wherein said secondary material isPEN.
 16. An injection molded preform (32) according to claim 13, whereinsaid primary container material is PET.
 17. An injection molded preform(32) according to claim 16, wherein said multi-layer constructionconsists of a three layer construction of an outermost layer (26) ofPET, a core layer of gas barrier material, and an innermost layer (26)of PET.